Wednesday ranked among the busiest sessions on Wall Street in recent weeks, with major stock moves spanning biotech, semiconductors, beauty and AI chips. Moderna and Merck delivered landmark cancer vaccine results, Marvell Technology struck an expanded AI chip deal with Google, Estée Lauder raised its profit outlook, and SK Hynix unveiled one of the largest share buybacks in semiconductor history.

Moderna and Merck Score Landmark Cancer Vaccine Results

The biggest story of the day came from Moderna and Merck, which announced positive late-stage results for a personalized mRNA cancer vaccine used alongside Merck's Keytruda drug.

The treatment, developed under the name mRNA-4157 (V940), met both primary and secondary endpoints in a Phase 3 melanoma trial. The vaccine is designed and manufactured individually for each patient based on mutations identified in their tumor. The data stands as one of the strongest pieces of evidence yet that mRNA technology, best known from COVID-19 vaccines, can be applied to cancer treatment.

Moderna shares surged sharply, making the stock one of the day's biggest movers, while Merck rose around 10–11%.

Both companies could now use the data to support regulatory filings. If approved, the treatment could open a major new commercial market for personalized cancer vaccines.

For Merck, the timing matters. Keytruda, which generates roughly $30 billion in annual sales, is one of the world's best-selling drugs, but its key patents begin expiring later this decade, which makes new combinations and uses for the drug a top strategic priority.

For Moderna, the result carries added weight: revenue from its COVID-19 vaccine has fallen sharply from pandemic-era peaks, and the company has been working to show its mRNA platform can succeed beyond COVID.

The Moderna and Merck results may prove to be one of the most important biotech developments of 2026. If the vaccine shows similar results across other tumor types, it could open a new chapter for both companies.

Marvell Technology Lands Massive Google AI Chip Deal

Marvell Technology was another standout on Wednesday after announcing a large expanded partnership with Alphabet's Google focused on custom AI chips.

Under the arrangement, Google received warrants that could allow it to purchase up to $12.2 billion worth of Marvell shares if certain targets are met — an unusually large equity component for a semiconductor supply deal. The broader deal could generate around $120 billion in revenue for Marvell through fiscal 2033.

The partnership reflects a growing trend among large technology companies to build custom chips designed for their own AI workloads rather than relying solely on Nvidia GPUs. Google has designed its own TPU AI chips for years, and Amazon and Microsoft have introduced custom AI chips of their own, turning designers like Marvell and Broadcom into key suppliers to the largest cloud companies.

Broadcom, which also supplies custom AI chips to Google, moved lower on the day as investors weighed whether Marvell might capture a larger share of future orders.

Estée Lauder Jumps 18% on Upgraded Profit Outlook

Estée Lauder jumped around 18% after issuing a profit forecast for fiscal 2027 that beat expectations. The company expects adjusted earnings of $3.10 to $3.35 per share.

The beauty giant has spent several years dealing with weak demand in China and in its travel retail business. The new outlook suggests the turnaround under CEO Stéphane de La Faverie — who took over in January 2025 and launched a restructuring program that includes job cuts — is starting to gain traction, with strong performance from premium fragrance brands including Le Labo and Tom Ford helping support the improved guidance.

SK Hynix Launches $28.6 Billion Share Buyback

SK Hynix, a major supplier of high-bandwidth memory chips to Nvidia, announced a $28.6 billion share buyback program — one of the largest in semiconductor history.

The company also pledged to return more than half of its free cash flow to shareholders between 2025 and 2027.

SK Hynix has been a major beneficiary of AI-driven demand for memory chips used in data centers. Alongside Samsung Electronics and Micron, it is one of three companies that dominate global memory production, and it has been the leading supplier of high-bandwidth memory, the chip category most closely tied to AI accelerators. The scale of the buyback reflects how much its financial position has strengthened as memory pricing and AI demand remain strong.